1. Technical Field
The disclosure relates in general to a semiconductor structure and a method for forming the same and more particularly to a MOS and a method for forming the same.
2. Description of the Related Art
In the semiconductor technology, the feature size of the semiconductor structure has been reduced. In the meantime, the rate, the efficiency, the density and the cost per integrated circuit unit have been improved.
For example, a method for increasing a breakdown voltage (BVdss) of a semiconductor structure such as a LDMOS or an EDMOS is decreasing a dopant concentration of a drain region and increasing a drift length. However, a specific on-state resistance (Ron,sp) of the semiconductor structure is increased due to the method. Therefore, the semiconductor structure could not obtain a trade off between the BVdss and the Ron,sp for obtaining a desired small figure of merit (FOM=Ron,sp/BVdss).